<template>
  <div>
    <ul>
      <li v-for="(item, index) in arr" :key="item">
        {{item}} ---{{index}}
      </li>
    </ul>
    <button @click="btnFn">走一走</button>
  </div>
</template>

<script>
export default {
    data() {
      return {
        arr:["吃","喝",'赌']
      }
    },
    methods :{
      btnFn() {
        this.arr.push(this.arr[0])
          this.arr.shift()
      }
    }
}
</script>

<style>

</style>